If you read through all the hundreds of posts earlier in the year after the whole "locationgate" businees hit the press, you can figure out that these now openly acknowledged services relate to the same information Apple has been collecting from its mobile device users for over a year or more.
http://www.macstories.net/news/breaking-apple-responds-to-location-log-scrutiny- with-extensive-qa-response/
(see item #8 in the QA)
The actual press release from Apple - http://www.apple.com/pr/library/2011/04/27Apple-Q-A-on-Location-Data.html
While there is less information on the overt Location System Services listed in iOS 5 specifically, it seems pretty clear to me that all they did was move the information from a hidden log file on your phone to openly acknowledged services that you may opt in or out of.
I know some people think something like cell tower search somehow enhances thier phones connection, but stop and think about it for a mintue. A cell phone is just an omni-directional 2-way radio. It takes a fraction of a second for it to scan the assigned carriers bandwidth to detect tower signals, handshake with the strongest available signal and establish the cellular service connection. Why on earth would it need to run a program to check its location with some database of tower locations and then start scanning for one? That whole process would be phenomenally slower and more complex than just having the radio constantly scan for the best signal within it's assigned bandwidth and with which it can complete a handshake with.
The cell tower search feature provides location based info to Apple to aid in their location services by non-GPS fix (ie. cell tower triangulation), as well as giving them data to potentially sell back to the carriers about use and connection congestion of their networks. Eg. where and when is the most iPhone use occuring on AT&T, or Verizon, which cities have the most consistent use, are they using corporate towers, leased towers, or internationally roaming somewhere. And don't forget, google collects similar data from Android users so the carriers could purchase access to data that lets them compare what their vairious device users are doing, where and when. That lets them target sales, promotions, specific regional advertising, infrastructure build-out schedules and all sorts of useful things.
The one I do not know about is the compass calibration. As I say, disabling it does not impede your compass app from actually calibrating when it prompts you to, not does it affect any location based display feature in the Maps app (or in my Motion GPS app or any other map app I have). Since the reason the compass needs calibration in the first place is due to electronic interferance, perhaps it provides information on where/when iPhone users are experiencing interference, and where location based services might experience errors. Note that Android users can now get map location data inside malls and such, which must use cell signal triangulation (since no cell phone I've ever used gets a GPS signal inside a big building like a mall), and those are also likely to be areas with tons of interferance, so location based services inside buildings (ones with internal cell service antennae) might benefit from such data.
Again, I'm not inherently against this data collection, and people can choose to participate if they think it worthwhile or if they see some of the potential uses as benefitting them in the long run. I however have disabled all six of those Location Based System Services just because I don't want them running. Even if they where to only decrease my battery life by a tiny percentage, I'd prefer to not have them running at all.
And we won't even get into the economic/social philosophy of why I should blindly particapte in something for nothing, when that something gains the collector of the data potential huge revenue gains over the long term.
