Google are entering a period of house-keeping and it seems to have resulted in a general 'tightening-up' on rules and regulations for Adwords users. We're promised a whole raft of enforcement directives over the next few months but the most recent that's come to light is in the realm of Sitelinks.
If you're not using Sitelinks - and you should - they're small additional links that can appear with your ad when it is shown either at the top or bottom of Google search results. You can read Google's description of Sitelinks and how to get them going here.
So what's the news? The policy for Sitelinks is that each link must point to its own landing page and that landing page must contain 'unique content'. So if you have a Sitelink for TVs, the landing page shows TVs, if you have one for Blu-ray players, the landing page is filled with Blu-ray players, etc. Apparently, some bad people have had some or all of their Sitelinks pointing to the same landing page or pages with the same content and Google wants to stamp this out.
Apparently (as usual) enforcement will begin with new or recently changed links so you've got a short while to get your house in order. It doesn't sound as though Google are going to completely suspend your account if your links aren't up to scratch; they'll merely refuse to use/show them but it's worth making the effort as they're really very useful things...