The Milestones tab is the second tab in a users Profile Stats, as the name suggest this tab shows a users milestones. This tab have three modules.
The first module shows a list of the users milestones. The first milestones are 1, 10, 50 and 100 caches, after that and up to 1000 caches every hundred cache is considered a milestone. After 1000 every five hundred cache is considered a milestone. At the bottom of the list the users most recent cache is shown, even if it is not a milestone.
Different milestones at Project-GC vs Geocaching.com
The milestones on this tab may not match the milestones shown in the user's Geocaching.com profile for multiple reasons. The milestones at Project-GC are calculated and not fetched from Geocaching.com. At Geocaching.com the user can chose to lock their milestones to a specific cache even if it's not the milestone that is calculated by Geocaching.com, this is not possible to do at Project-GC. An other reason is that the data provided for geocaches in the Geocaching LIVE api and the data provided for Lab caches in the Enterprise API does not match, this means that Project-GC does not have enough information to determine the order between Lab cache finds and other geocaches if they are made on the same day which might cause problems when planning a special cache for a milestone.
The specific problem is that each geocache log has a date and log ID which is a number, this identifies which log belongs on what date and in which order they come on that day. For Lab caches, a timestamp is provided. This identifies which date the lab cache was logged on, but it also has the exact time. The result is that Lab Cache finds can be sorted in the proper order, but since there is no timestamp for other geocaches it is not possible to know which way the sequence of all cache finds occurred on a particular day.
First cache by country
This is a list of the first cache the user found in each country they have found caches in. The list shows date, country, cache type, GCcode and the milestone of that cache.
First cache by cache type
This is a list of the first cache the user found of each cache type they have found. The list shows date, country, cache type, GCcode and the milestone of that cache.