Hey, I have noticed a lot of sites link to the 3 main search engines, does this benefit in any way for SEO or ranking?
Your will benefit if the 3 major SE's link to it. You can have a better PR. You can gain a link juice from those 3 major SE's because they are quality links. Traffic also is another benefit. But my concern is, it's hard to link your site in major SE's not unless you are doing PPC.
If you outbound linking to website/page in your theme, you will gain SERP. Just linking to SE won't do any good... Good luck, K.
Linking TO related content could be beneficial. I doubt that linking to a search engine would be helpful, unless your content is about search engines.
There is a belief that linking to related content is helpful, as it would help the user, and that is what is most important. I think the OPs question is related to that belief. However, I don't think there would be much, if any benefit, for a search engine, as the content is so general and is probably filtered out as providing any benefit.
There was a rumor going around back in about 2003 when i was on SEOChat alot that linking to Google will increase your rankings... It was knocked on the head back then but people still come up with it.