Rev's personal congrats standards for the Level Up Lounge:

Exp Levels & Milestones
Level 10 or above.
1,000 exp or above.

Blam/Protect Levels & Milestones
Private or above
1,000 B/P or above (I usually won't say Police Sergent)

BBS Posts
1,000 is the minimum with only multiples of 1,000
Special number like 1337 or repeating digits like 7777 if the Lounge is slow.

Reviews & Review Responses
100 Reviews for all media (Flash, audio, and art).
100 Review responses is also the minimum required.

Whistle Level
Any level up in whistle status above Bronze. No congrats is not given if the user is re-earning a previously obtained whistle level after being demoted.

Medal Points
10,000 Medal Points is typically the cut off, though if the LUL is slow 5,000 would be acceptable.

Other Stuff
Real Life birthdays and Newgrounds account anniversaries are good. In addition, "Total Stats" achievements, which are all your stats combined. (EXP + B/P + POSTS + REVIEWS) above 10,000 are congratulated.