This is just a curious question: If someone were to ask you [eg. on an interview or something], what is the toughest aspect of SEO, what would you answer? I think it would be interesting to see some of the responses...
The time waiting to see results is a great answer and the time it takes to acquire enough backlinks to overtake a competiter in the make money online business.
Delayed gratification. How every if you are blogging just keep plugging away with great articles. As you PR and link grow your old articles will start ranking higher and the traffice will roll in - for free
The time is definitely a really tedious part of doing SEO ABSOLUTELY - I've been studying SEO for about a year and a half now (which isn't that long, but...) I still can't believe how much effort and persistence it takes. I asked this in SitePoint forums too, and one person responded, "Getting the people who the project is for to be patient and understand exactly what is going on. Unrealistic expectations is one of the two banes of SEO." That's a pretty good answer...
I hate link building (probably because i'm not that good at it)... but especially from high PR and relevant sites
Link-building and waiting to see results, especially on new sites. Thinking you made a mistake and then the uncertainty while you wait to see if SERPs go up or down .....
I think the hardest part is ranking for thousands of longtail keywords (that are actually searched). It requires tons of patience and determination, lots of content and articles, good onpage-seo, and usually lots of backlinks as well.
Quality of content, followed by the quality of your backlinks. Yes, the content part isn't directly related to Search Engine Optimizing but is usually where most webmasters attempting to do SEO fail; therefore making it usually the hardest part.
Effective link building, without a doubt. Particularly where markets dominated by large corporates with huge paid link funds are concerned. Even the most intelligeint natural link building will struggle to compete with a big money 1,000,000 link, link buy.
I would have to disagree, mostly small based companies or moon lighting webmasters are the wholes who buy up tons of text links; not to mention this is what most SEO firms consider "optimization" . Most major companies are already branded and have a user base to start off of.
Link begging, I hate it. Creating new sites, without deep pockets for funding link buys and/or without having a network of sites to promote them with for a jump start, really makes it difficult to get new sites started.
Quality content will bring upon quality links, you don't need to spend a dime to create quality unique content that people will "want" to link to. I can give you some prime examples if you'd like. Concentrate on "content" after all the on-page optimization is optimal.
My original statement was based on cold, hard, facts. In my day job, I come up against this kind of thing day in, day out (I've even managed campaigns where substantial, and I mean substantial, link buying goes on). In certain, competetive markets the only way to the top is through link buying. The level I'm talking about is anywhere between $20,000 - $100,000. Many people baulk at these figures, or simply don't believe them. If you take the time to consider the value of the traffic in massively competetive markets, not to mention the cost of the same traffic via paid search channels then you'd see, very clearly, how such a thing is viable. I'm sure smaller businesses take this approach too, however not on a scale that cannot be overcome through well planned and well executed SEO. The former however, is difficult to compete against without the luxury of a sizeable budget.
Majortiy of links bought are of low quality or no relevance; I don't know which companies you deal with, but with the risk of Google penalizing sellers I wouldn't recommened forking over any money towards buying links; what a waste of investment would that be. I agree with your point, that someone with enough money could in fact purchase enough links to obtain high search results, this why I favor Google's crack down on it. However, it's not as wide spread as you would think, maybe in your industry or niche, but if thats the case why haven't you been reporting your competitors Content is the number one factor in search results, not backlinks. Quality content provails and will always get "natural relevant" backlinks of high quality. Want a example? I knew you did...... http://developer.att.com/developer/index.jsp?page=goToMarketArticle&id=24100189 Funny, At&T linked to my small simple SEO knowledge database (see my signature). I only noticed this while going throught my external backlinks via Google Webmasters Central. Proof that quality content will bring the links you need... content is king!
Seriously, report your competitors and you'll see that Google do nothing about it. In a sense, they've backed themselves into a corner with a predominently link based algorithm by essentially allowing top positions to be effectively 'bought'. Once the majority of the best quality web sites per market have begun buying links, what can they do? They can't ban or severely penalise them - if they did that then the quality of the results would be poor. There's potentially a risk, I agree. However, the revenue being enjoyed via a quick rise the very top for the most lucrative of terms makes this risk worthwhile. 6 months there effectively pays for 24 months on page 4, for example. Of course, quality content will bring you links. Where a large budget exists though, is that the quickest way to the top? In my experience, it's not. And it's that which makes the decisions of these large organisations. I'm by no means an advocate of link buying - it's not a route I'd commend at all. However, it is in wide use, and it is working; for the time being at least. The whole 'content is king' thing is a great notion, but looking at the SERPs in the most competetive market, I can't help but feel that it's just a Google ideal, naive and outdated. Perhaps this will change in the future, but at the moment that seems to be the way things are going. I can provide some very clear examples of this concept even in less competetive markets if you're interested - just give me some time to put some figures together.