To answer the QOTD, well you said it yourself: The 1st is corporate reorganizations, and the 2nd is regular portfolio transactions.

2 popular examples of DGI include mutual funds and telecom stocks. I own some Verizon and AT&T shares and I have my brokerage automatically reinvest the dividends on behalf of me. Reinvestment is an excellent way to compound your gains year over year if you're doing a long term strategy. I expect most people buying dividend stocks to be holding long term anyway.

Cheers and here's to a wonderful 2018!