Twitter Traffic Issue

Hello,
I have accounts with 5-6k + followers.
When I tweet a link on those accounts shortened by bit.ly to track clicks, I get 100's of clicks.
But on my site, Sitemeter only records few visitors, like 4-5 visitors.
The site in question is a wordpress blog. My wordpress users online plugin shows loads of users online as well.
But sitemeter and my advertising company aren't recording them.

Any guesses?

Thanks

I have one guess -- after manually looking through my logs.

Many of the *clicks* are coming from bots that are:
1. New search engines attempting to chomp as much information as possible
2. Companies that keep track of brands, i.e. reputation checkers for mid to large brands
3. Content verifiers, i.e. "is this content really the site it links to? Does it give credit"
4. Bots -- and more bots.

If possible get your raw log data (most likely in ELF format) and run it through a stats program like:
Once you get the report you'll see the gaps in what is happening.

Also, bit.ly inflates its numbers. It has an aggregate count and an individual count for a link -- depending upon how you are using it. Also each bit.ly *click* is not necessarily unique.

Hope this helps....