Conversation so far:
What were George Bernard Shaw's first political activities?
On 5 September 1882 George Bernard Shaw attended a meeting at the Memorial Hall, Farringdon, addressed by the political economist Henry George.
Was George Bernard Shaw an active member?
George Bernard Shaw was not impressed by the SDF's founder, H. M. Hyndman, whom he found autocratic
Is there any additional information about George Bernard Shaw's time with the SDF?
George Bernard Shaw doubted the ability of the SDF to harness the working classes into an effective radical movement and did not join it.

Question: What did he get involved with next?
Self-contained rewrite: What did George Bernard Shaw get involved with next?