Yes, there are many pop-ups, and potential malware, (both be solved using a decent ad-blocker and antivirus/security suite)
The main issue here is adult content (no warning). Then again, you don't stumble on an xxx picture's url by accident. Anyone who encounters adult content has to have purposefully looked for it... ;)
As per today imgserve.net is detected as a spam sending domain or is misused as a spam server.
Possibly dangerous to visit as the server/site could also be infected with malicious content or viruses.