Do you think that internet businesses usually require less startup investment when compared to other offline businesses? Or do you think that internet business require more startup investment?
depends on what kind of business you are talking about. there are sites that cost millions to buy. on the other hand, you can setup a blogger blog free of cost, put some content and adsense ad and call it an internet business
Practically it can be almost free without needing a single cent of investment, if you go to public library and use the net connection, setup a free blogger account, create a blog, get accepted in adsense/join affiliates to market a product and start making money.
In general yes, but in the end every business needs investment in terms of advertising and promotion. But when comparing bricks and mortar to web sites it obviously going to be cheaper. Any newb with a Pc and net connection can knock up a website, that same newb could not build a shop if they had bricks and mortar.
Generally spoken you would need less investment for the internet then the "real world". But when spending a lot for marketing in the net...