It seems that the search engine submission sites just want your email address to so they can market to you. Are they all scams?
I've never bothered submitting to search engines. If you build links and have decent content, the search engines will find your site.
Let's allow search engines to find you. I agress as you have unique relevant content and back links to the website they will automatically finds your existence you do not have to go for search engine submissions. Just concentrate on your website and promote it ethically rest search engines will give importance for your efforts. Expect miracles but not very often.
Search engine submission sites are not scams. If you constantly update your site content and and have good daily traffic, then you'll rank pretty high in them. Of course, if you submit to a free search engine, then they are going to market to you, so they can make up the expense. It's common sense.
You'd be better off just submitting some of the articles on your website to social bookmarking sites like digg, stumbleupon, del.icio.us etc. The search engines will soon pick up the content and index it because these sites get crawled many times a day.
The fastest way to get indexed is to submit your content to Digg, it will get index in an hour, tops 3 hours.
I would not call them a "scam." Some of those companies can provide a service. But I would not spend a lot of money of them. If you have plenty of backlinks, search engines will find you. There is no real need to submit to anything. But some people find comfort in knowing that someone has submitted their site to the search engines.
I have had alot done a ton of link submissions to these sites. Honestly, I have not seen much benefit to these sites.
Perhaps not scams but taking advantage of naive webmasters? Yes! When I first got into IM many years ago now, I purchased a search engine submission site package which was a complete waste of money. What's the point in getting your website listed on search engines which won't generate any traffic for you? Focus on Google/Yahoo/MSN and forget the rest.
Submitting your website to every search engine is an incredibly time-consuming process. There are hundreds and hundreds of them out there - no doubt, you've come across the companies who'll submit your website to 1000 search engines for you. Search engine professionals know that the vast majority of these search engines have a very low usage rate and will drive hardly any traffic your way. In fact, it's only a handful of search engines that drive the majority of traffic from search engines to websites.