Language corr. (1)

l. 5: spelling of "indem"
l. 29: spelling of "Benutzer-Online-Liste" (I guess that's the technical correct term, isn't it? Please check on that)
l. 34: "Mitgliedern" (Dative-case)
l. 36: "Benutzerrängen" (plural prefix was added) as well as deleting the comma  in front of "sowie" ( (that's due to the last German spelling rules)
l. 87: including the comma due to focus
l. 98: "Signaturen", the /n" was missing
Language corr. (2)

l. 207: "Benutzerkontos", I've added the Genitive-suffix /-s/
l. 406, spelling of "Benutzer-Online-Liste"
l. 439/448/457/466: You've switched from third person to informal "you", thus I changed that. However, I'm note sure wehether the informal version is the standard text within social networks. If so, re-write my changes. Moreover, I've a added a comma because of grammatical rules (zweo verbs).
l. 557: I've deleted "aktuelles" as birthday implies one's actutal birthday and not e.g. the one two years ago or the one in the future.
Language correction (1)

I've noticed several phrases where the definite article would be appropriate due to stylistic reasons. Accordingly, I've inserted "the" in these lines: 5, 30, 31, 32, 36.

Furthermore I've inserted "one's" as a reflexive determiner in the lines 20, 23 and 25 (to establish the connection between the subject and object).

Within the lines 27-29 you wrote "see" and I wanted to know whether "view" wouldn't be more appropriate within this context? I think it's more likely to assume users to view sth., not the real visual seeing of sth.If you agree, let me know and I'll change the verb. 

Then I've inserted the "with"-gerund-structure in line 36, in order to the reveal the logical consequence of the two sentence parts.
Language correction (2)

1. A comma was added in the lines: 53, 56, 174.
2. stylistic improvements applied in the lines: 75, 168.
3. Translations prepared in the lines: 90-103.
4. Prepositional correction in line 170.
5. You wrote "Unfollow" in line 160, which would be a neologism. Maybe this is the term used on Facebook (?), so you copied that. Nevertheless, I'd propose "De-follow" due to morphological rules(the type of prefix needs to match the root of the verb.
Language correction (3)

- a changed term in line 199;
- spelling corrections in line 211, 212, 252;
- plural-suffix was added in line 212;
- stylistic changes applied to line 212, 245;
- a comma was inserted in line 235, 251;
Language correction (4)

Changes due to tense: 311, 341
Changes due to stylistic reasons: 311
A comma was inserted in line 333
Words were changed in the lines: 406, 415, 424 and 433
A suffix was added in the line 447
Language correction (5)

l. 21 spelling (I forgot to mention it earlier, sorry)
l. 449 word change
l. 501 tense was changed
l. 567 definite article was added 
l. 567 style adjustment
l. 579-584 translation of the ranks, new suggestions
Stylistic analogy

line 59 and 62 (see suggestion by TimWolla in "language corr. (2)")
Added missing language variables
Small language optimization
Added missing language variables
Language fixes by @Gabbid