The Openlife grid is still alpha (or early beta) code, so naturally you're gonna see these things. The "already logged in" thing is a bug when logging out, sometimes the agent doedn't log out so you get an effect similar to when you crash on SecondLife and try to log in again. Sometimes you agent may still be there so it tells you to login after 5 minutes or more. It's the same here, except that there is no "5 minutes", just login again so it forces the old agent out.

The whole grid is like early SecondLife, so you may not see too many people logged on at the same time. Another thing is that on SL, when you open up the map you get "green dots" where there are people. That feature isn't fully implemented, so the map looks empty. You can still detect nearby avatars that are in the same, or neighbouring sim, but not much more.

The vision of OpenLife, as far as i got it, is to be like the LindenLabs of the opensource grids. You can purchase sims at a much lower price than what LL offers, since the OpenSIM code is free, the price per sim doesn't need to be raised artificially, its more or less the cost of running the servers. Think of it as a refreshing change from LindenLabs' monopoly. Also, the OpenLife grid is an early adopter of new technology. It's the first grid i know to use (even partially) experimental code developed by the OpenSIM and RealXtend teams, with features like importing meshes, python scripting, mesh avatars, dynamic-content textures you can see a URL on etc. Also, there is an awesome RealXtend update comming along with an early beta of their Global Avatar System, which should allow you to jump from grid to grid while keeping your inventory.