The document discusses several online services including Slideshare for hosting presentations, Twitter for microblogging with tweets of 140 characters or less, Facebook as a large social networking service with 750 million users, Lang-8 for language exchange with selection of native and target languages, and PIRKA as a social service for picking up trash.

1. Web services

2. SlideshareAn online slide hosting serviceUsers can upload files; Powerpoint PDF, Keynote

3. TwitterA microbloging serviceSend & read text-based posts of up to 140 charcters, called “tweet”200 million users, over 200 million tweets per dayFail whale

4. FacebookSNS (social networking service)750 million usersMark Zuckerberg (The Social network)

5. Lang-8A language exchange SNSThe company is based in Kyoto, JapanSelect native language & target languages

6. PIRKAA social picking-up trash service