I'd hate to break everyone's party... but it's not that simple.
Oh, you want a reason why it's not that simple? Then keep reading...
The main search-engine to use 'link back' technology and the starter of this trend is the infamous Google. It's complex system weights websites on how many links they get from other websites and gives them a 'PageRank' worth between 1 and 10. Most websites average a three or so.
These PageRanks weight your page to turn up higher in results pages for
set keywords. These are typically the most used ones on the page and ocassionaly also include the one's you've put in your meta tags.
Instant increases in your 'PageRank' score include a listing in DMOZ (Open Directory Project), it will give your site a bit of a 'boost' and of course if the AltaVista/AOL/Excite etc. co-branded DMOZ pages have your link it will also boost your 'PageRank'.
Another way to boost your 'PageRank' dramatically is to put the keywords in an appropriate domain.
http://www.harry-potter.com/ will instantly get a higher ranking than
http://topstuff.hosting.com/mystuff/harry-potter/ when searching for "Harry Potter". Although this can be changed and you can get higher results if you manage a very good 'PageRank'.
'PageRanks' mainly work by giving you points for
quality pages that link to yours, that are
relevant. If for example you are running that Harry Potter website, getting a link on a Harry Potter website of similar popularity, it is going to be better than on a popular FreeWebSpace site. This is because of
relevance.
Quality on the other hand is a measure of the quality of the page... if the page has two links linking to it, in it's 'PageRank' and only one external link out it's going to have a much higher 'PageRank' than other websites (and be more worthwhile to get a link from). Where as a website with two links in and twenty external links will have a lower 'PageRank' and will typically be of
no benefit to your website's 'PageRank'. If there is a website with two links in and two-hundred and fifty external links out, it will have a
very low 'PageRank' and it will be of disadvantage to any websites it links to.
So yeah... sorry to break all the fun but your best bet is to affiliate with similar websites on your mainpage, something you should be doing already and the Search Engines should reward you for it. If you spam them, they'll try and dis-advantage you for it.
Simple huh?
Copyright MMI, All Rights Reserved. Information sourced was from Google's website, interviews with Google staff over the 'PageRank' system and several promotion websites. Not all statements can be assured as Google has not officialy published their way of counting PageRank scores, although we've got a pretty good idea... I think. Any assumptions etc are of my own personal opinion and should be taken as such, not as an authority fiqure.