LinkedIn recently added "Seniority Level" as an Advanced Search filter accessible by users with premium accounts.
Tagging it as a "Beta" feature is a bit of an understatement as the feature misses the mark completely, as in it's current state, only seems to be matching profiles where the user's title begins with the keyword of the chosen level.

If "Director" is chosen, Seniority Rank Beta only matches users with a title beginning with "Director".
In other words, titles such as "eBusiness Director", "IT Director", etc., will not be found.
I would steer clear of this feature until additional development generates better results. For the time being, use with caution.
Here's a quick test illustrating the issue.
I'll search for:
Companies: Kimberly Clark, Kleenex
Rank Filter Position: Director-level only
Title Search Terms: analytics, contact, commerce, eBusiness, ecommerce, experience, information, interactive, internet, online, web

Try this search here: http://peopletoucher.com/linkedinsearch/?sel=Ykimberly_clark,Ykleenex,Winformation,Wexperience,WeBusiness,Winteractive,Wanalytics,Wcontact,Wweb,Wecommerce,Wcommerce,Winternet,Wonline&rf_1=3&rf_2=3&fr=6&syll=0&loc=A&cou=BL&zip=&rad=4
Now try the LinkedIn Seniority Level Beta filter here: (premium account required)
http://www.linkedin.com/search/fpsearch?title=%28information+OR+experience+OR+eBusiness+OR+interactive+OR+analytics+OR+contact+OR+web+OR+ecommerce+OR+commerce+OR+internet+OR+online%29¤tTitle=C&company=%28%22kimberly+clark%22+OR+kleenex%29¤tCompany=C&searchLocationType=Y&keepFacets=keepFacets&page_num=1&facet_SE=5&search=&pplSearchOrigin=MDYS&viewCriteria=1&sortCriteria=R&facetsOrder=N%2CG%2CI%2CED%2CFG%2CL%2CDR%2CSE%2CFA%2CCS%2CF%2CP%2CCC%2CPC&redir=redir
I found a few less matches using LinkedIn Seniority Level Beta, all of which had titles with "Director" as second or third words in their title.
What do you think about this feature? Do you think LinkedIn will eventually nail Advanced search to the extent possible with boolean operators used by a seasoned pro? Do you think the Peopletoucher Search Engine will someday become obsolete?
As suprising as the answer may sound, I hope so! I'm hoping the service provided on this site will eventually be weaved into LinkedIn advanced search.
In the meantime, we'll keep this site running until they do.
Please share your opinon in the comments.