Since nobody seems to have answered your original question in detail:
50 posts--TMF Novice
150--TMF Regular
300--TMF Expert
600--TMF Master (although I have always contended that it should be TMF Mistress for women members)
1,000--first level Red Feather
1,250--second level Red Feather
1,500--third level Red Feather
1,750--fourth level Red Feather
The four-levels-per-thousand with a different color continues on upward until 9,750 for fourth level White Feather, with the colors as follows:
1,000--Red Feather
2,000--Orange Feather
3,000--Yellow Feather
4,000--Green Feather
5,000--Blue Feather
6,000--Indigo Feather
7,000--Violet Feather
8,000--Black Feather
9,000--White Feather
These levels have been reached so far at 10,000 and above (where the "first, second, third, fourth" are no longer used):
10,000 Level of Cherry Feather
11,000 Level of Tangerine Feather
12,000 Level of Lemon Feather
13,000 Level of Lime Feather
14,000 Level of Blueberry Feather
15,000 Level of Raspberry Feather