Some search engines rank your site by link popularity, I think. I'm still a newbie after 15 months. My question is, is it the actual link they look at or is the text for the link? And if majority of links point to a different page than your homepage, will that page be ranked higher or your homepage? and will it help your homepage if other pages are heavily linked?
I used to get about 20 google/yahoo hits per hour to my index page but sometimes they would completely stop for a week or so and then start back up. Now SE hits are down to about 20 per day. I checked my server stats and saw that about 1000 sites link to my site this month and my third party stats say over 3500 sites link to me. With over 200k unique visitors so far this month (12/21) and only 20-100 search engine hits a day, it just doesn't seem right to me.
Each search engine has it's own algorithm for evaluation of popularity. Google, for example is looking at factors that include the actual link text (a keyword as the link is more helpful than your company name and the surrounding text for determining the theme of the page linking to you.
PageRank for Google is page specific, however, if you have more links to a subpage, that could have some helpful effect on your home page PageRank and SERPS. So, there is a correlation built in to affect PageRank of the home page and other pages if you have approprate links to several pages in your site, pages that also well interlinked to your home page.
I do have more links to a certain subpage than my homepage. If not, it's close and there will be soon. I just hope to move up on the SE's. The text links pointing to the subpage have nothing to do with my homepage at all, name is different, content is different. I only have one link from my homepage to the subpage and vise versa. It's only been a little over a month since all the links to the subpage so maybe it takes a while for SE's to recognize it.
As for where all the hits are coming from? Apparently some sites that look like a cheap geocities layout type that you would think has no visitors, may actually have huge amounts of traffic. I was shocked too when I saw the numbers skyrocket. I just got lucky I guess.