The example sentences on this website are from the Tanaka Corpus via the Tatoeaba project.
I wanted to add some example sentences to add value to this website and also aid my own learning. I used to use the IKnow api to automatically display lists of sentences but had to stop using that when IKnow became a paid service and they dropped the api.
So I started entering sentences individually to my own database which was a slow and laborious task. However I came across the Tanaka Corpus and Tatoeaba project and realised life is too short to re-invent the wheel on such a massive scale. So I downloaded some of the files from the Tatoeba website, whacked them into Access, stripped out the non-Japanese/English sentences, then imported them to the mysql database which hosts my list of verbs.
Not necessarily, please read the caveats on the above websites
Anyone can sign up at Tatoeabo.org and contribute. Eventually I may refresh this website with updated data from Tatoeba. Alternatively you can enter example sentences in the comments section at the bottom of the relevant verb conjugation table page.
Any Romaji translations have been added by me, mainly by using Google translate. This is part of my own learning process.