When my adwords clicks are not matching to my prosper202 clicks, what does this usually mean?

This is on 1 campaign

adwords says 280 clicks

prosper says 231

Please go to VISITOR tab and change view to SHOW ALL CLICKS instead of SHOW REAL CLICKS, hit SET PREFERENCES and wait for it to load. This should show you the total number of clicks Prosper202 have received and should be a number greater than 231.

What happens is there are a set of real clicks and a set of filtered clicks. Filtered clicks are clicks that do not count towards the real click count. Examples of some filtered clicks are Search Engine Bots crawling your ad to see whether it's approved or not, or repeat IP addresses that have clicks on your ad more than once, etc...

It is possible that 202 may have filtered more clicks than what Adwords may have filtered, hence the discrepancy. In roughly 2-3 months from now, hopefully sooner, 202 will release a new tracking system that is API based that is plugged directly into the search engines providing 100% accurate cost. For now however, you're going to have to gauge the difference while we're working to get this out. Sorry for the inconvenience.

prosper is still only showing 255 clicks

280 - 255 = 25 clicks still not counted for

Thats a good portion of clicks, almost 9% of the clicks missing that I paid for...

... could it be my hosting? what else could it be?

the original 280-231 = 49 which is 17.5% missing clicks

could it really be adwords charging me twice for 2 clicks from the same IP? why would their system be set up like this

The way adwords work with regards to similar IP as far as I understand is if they click within a certain timeframe, it gets filtered. After that certain timeframe has pass, you may be charged for the clicks. It is also on a case by case so the rule isn't finite. Here is some info it lists:

Adwords and IP

As far as why there is a shortage, it's hard to say to be honest. In reality, when they click on the ad, it should have already registered the click because it's the first thing that hits. There could be a couple theory as to maybe the ad clicked but for whatever reason the page didn't load through to the redirect. The javascript got dropped, etc... It really is hard to determine any precise point as to why the count is off but in nearly all the cases, 202 overall should have a higher count than adwords. In this case, I'm not sure why it's lower even with SHOW ALL CLICKS.