The new feature they probably should have highlighted more clearly is People Search Alerts via Email.
You can now save up to 3 searches for common keywords, job titles, company names, or other topic-specific searches, and get them emailed to your inbox on a weekly or monthly basis.
I do several of these types of searches via Google alerts for company- & product-specific searches on news & blogs. Now you can also do them for people as well on LinkedIn.
Yotify also allows you to do saved search notifications via email for products for sale & other classified listings. Simply Hired does alerts for jobs. Spock is another service that does comprehensive people search. (disclosure: i'm an investor in Simply Hired, and an advisor to Spock. i'm a friend of the founder of Yotify, Ron Bouganim. and i'm an informal advisor to LinkedIn, but not on this topic)
i haven't done a thorough review of these types of search & notification services, but there are many of them. That said, their value is directly correlated to the quality of their search (crappy search with notification isn't that useful... however great, targeted search with notification is quite useful).