Introduction by existing employee. Had a 1 on 1 interview and submitted my CV. Heard nothing for 3 weeks. I called the manager and he said he was keen but salary could be an issue. Over the next 2 weeks we spoke 3 times, resolved the salary issue and I was made an offer which I accepted.
The HR department were really slow and unresponsive in processing my info altho i was paid on time from the 1st month but had to supply them some docs twice as they "misplaced" the first ones!
I've heard of people who were made a verbal offer but IBM internal processes are so slow that it took 3+months for a formal offer to be fully approved by which time the candidate had accepted a position elsewhere.
Incidentally, although they ask permission to do all the background checks, they never called my previous employer, nor any of the people I gave as references and the credit bureau showed no inquiries so clearly their screening is not so thorough!