Question about those writings between an username and the profile picture

[kspguy77]

Hi! I was just wondering what those writings between the username and the profile pic are? For example for me there reads "bottle rocketeer" and some people have other "names", i know they are fun and meant to be so, but could someone provide a bit more in-depth explanation about those (e.g why are they there, what do those little balls under the writing mean and so forth)? I know, my english is a bit broken, i don't speak it as my main language.

[James Kerman]

G'day @kspguy77.

Both are basically ranks.  The top one (bottle rocketeer) can be modified in account settings/edit profile/member title.  The dots relate to how many posts you have made.
 

[Geonovast]