Rakuten: Their core and original business model, renting a part of web shopping mall to shop owners, are proven to not working well. Rakuten asks 500,000 yen (about US$ 5 thousands) for each shop owner to open virtual store, and of course, most of the shopper are in red. They are quite active to acquire/merge other companies. It might be because they need to find another core business. Many directors are graduates of US univ., MBAs. For western investors/companies, Rakuten might be easy to talk with. A director said their goal is to become a number one company in the world, to be bigger than Yahoo. Technically, there is nothing special.
Livedoor: Their core business is creating web pages for companies. Many companies have been using Livedoor because Livedoor is Number 1 web page developer in size. Livedoor surely has some skilled developers, especially in Perl. But as company become big, most of the work are done by mere novice workers. Many companies start complaining about its bad quality.
As many peoples know, it's quite important for IT startups to use marketing budget effectively, to dominiate market, to build up its brand. And we should not forget that most of their revenues come from barter sales. There is few real cash flow. Anyway, Rakuten and Livedoor succeed in becoming popular among ordinally people.