If you are an AdWords user, you need to read this article ASAP:

http://www.mediapost.com/publications/?fa=Articles.showArticle&art_aid=145284

Basically, if your advert appears in position #1, and consists of a headline in a proper sentence, then your 2nd line of text may be automatically moved up to the first line to produce a longer headline.

One of my colleagues experienced this which dramatically increased the CTR rate (Google’s goal), but without producing a material increase in quality traffic. Thus, all the additional traffic produced proportionately fewer conversions, resulting in a massive increase in CPL and total cost. This was not a good result, so the ad needed to be reworked (or the bid lowered so it would not appear as #1).

So, you should run an audit of your campaigns to see if ad copy should be updated. You may not want a full sentence to appear – or may want to change what it says so it is more accurate as a headline.

The reason more people click it is most likely related to the fact that it more closely resembles organic results.