So, do people buy .com for better ranking or just to make a good impression on their readers and that they remember it easily?
They do both. Unless your targeting a less competitive term I doubt that the domain name is going to count for much though. If you are targeting anything competitive, you are going to need much more than a good domain name.
hi .com domain name represent golbal presence of website and its services. If you want to promote your services or product for any particular country buy domain name related to those country like for australia com.au or for india .in or co.in etc.
Domain extension has some impact on SEO. So does the age of the domain and the domain itself. bluewidget.com can help quite a bit in ranking for the keyphrase blue widget or widget itself.
having the .com domain of your keywords will give you an advantage over competitors, as long as you match their on site seo and backlinks.
absolutely. From running multiple websites I can safely same the domain is the strongest "onpage" factor going for a website. After that title tags, but the domain name is very very powerful.
I have watched a Matt Cutts video about that he was saying that domain name is a little bit impact of seo if you can choose a domain name that is related with your main keyword it would help your google rank for sure what about extension of domain name ? I think it is about familiarity
Domain name has no influence directly... It is on-page factor that has influence on off-page factors... Domain name itself is nothing, but the power is in anchor text, so if you have keyword friendly domain name your will get keyword friendly anchor texts... And anchor text is one of the most important SEO factors...
It certainly helps if you are doing all of your onsite SEO and building links. It is not a replacement for hard work, but it does help in serps.
Domain name particularly gives your site an initial impression of what it is, but that's not really too important in terms of ranking. The complete URL can probably give more impact than the domain extension itself. I've seen many sites that are .info which rank higher than sites with .com extensions on the same keyword. Basically, it still boils down to content.
it seems to help but its not all. just like some ppl said earlier sometimes a domain that doesnt have the keyword can outrank one that has it. i guess this is where domain age/ back links/ and PR come into play
It's part of the picture, usually not overly important. Your meta-tags, titles and descriptions play a greater role in general.