In the last year or so, LinkedIn has added endorsements, tags for skills / expertise that members can apply to other members. They are sometimes referred to as 'lite' recommendations since they can be applied in seconds without much thought (LinkedIn displays a selection of possible tags and the endorser just clicks on the ones they want).
In general, it seems to do a good job showing what a person knows (eg., my top three are CCTV, IP Cameras and Video over IP). If you do not know anything about a person, it can give you a quick gauge of what they have experience in.
On the other hand, it's hard to know how good a person is at a certain area plus those with more connections will almost certainly have more total endorsements.
Plus, it can sometimes be gamed, as one IPVM member strangely showed:
The biggest issue I have with endorsements is that they make the LinkedIn news feed worthless as 70%+ of the activities are now endorsements updates. It's demotivated me from even going to LinkedIn's website anymore.
Btw, the LinkedIn tool I like the best is still the job changer notifier.