We'd like to write a Crawler that can Index User Profile so search can be done very quickly using Lucene, especially for Profile Properties which are hard to search for (from performance point of view)
1) Crawler should respect public / private / admin only security settings on profile property
2) Crawler should be able to re-index when any of the property is changed
3) Crawler should be able to delete from the index when user is deleted (both soft or hard)
Note - This was not part of initial requirement, however PM has shown interest in this area. I am marking it as low-priority for now.