Twitter was hyped as one of the greatest Internet businesses, yet it makes 7 times less profit than a company like Yahoo, that is loosing now for 15 years in the market.
That is also reflected in Twitters stock value, which lost 60% of it's value since the IPO.
Billions were literally burned by investors on this company because they will not even get back their investment.
As a developer I would never touch something like Twitter just as I wouldn't work for Yahoo, as it's a sure path to destroy your own career. (what career progress can you make in a company that will most definitely be irrelevant and likely even out of business in the next few years)
If they couldn't get their business model right after 10 years, they likely never will.
it was a SMS based broadcast service, no?, and it largely still is (only dropping the "SMS" part, but keeping all the baggage)