Your article was likely deleted per Wikipedia's criteria for speedy deletion because you did not establish why the person/group/company/website is notable enough for inclusion on Wikipedia. If the article was about...
- ...your band/group, your musical career, or a band/group you really like: All musicians and musical acts must meet the criteria for musicians and ensembles. For example, if you or your band have had a charted single or album, then you are notable. If you or your band is unsigned or has yet to release any albums through a major label or important indie label, then you are not likely to meet the notability criteria. You or your band need to be notable before you start the article. Being an "up and coming" band is not enough. Wikipedia is not for getting the word out about you or your band. Perhaps sometime in the future, you or your group will hit it big and you will be too busy touring and making records to think about writing an article and one of your fans will write it for you.
- ...you: All biographies on Wikipedia must meet the notability guidelines for people. You can make your own user page where you can talk about yourself, but there are certain guidelines you need to follow. Please note that Wikipedia is not a social network. If you are still in school and/or looking for a job, please do not post your resume or CV as such articles are not appropriate. Companies are not reading Wikipedia to look for people to hire. See also the guideline for writing an autobiography.
- ...your YouTube videos: I'm sure your videos are really interesting, but all articles about web content must meet the notability guideline for web content. While you might have thousands of views or hundreds of subscribers, unless some news organization has written about you, then you probably do not meet the notability guideline.
- ...the company you work for or you started: All articles about companies must meet the notability guideline for organizations. Please review Wikipedia's Business' FAQ and the article subject's FAQ.
- ...a website: All articles about web content must meet the notability guideline for web content. While it might have hundreds of page views, visitors, or members, unless some news organization has written about the website, then it probably does not meet the notability guideline.
- ...your friend or the person sitting next to you in class: I know, class is bbbooorrriiinnnggg with your teacher yammering on-and-on about something that does not seem relevant to your life, but please do not write about your friends. No, I can't "leave it up for a moment". All biographies on Wikipedia must meet the notability guidelines for people. If you used any of the following words in the article, then your friend isn't notable: "beast", "amazing", "cool", "legend", "awesome".
- ...your wife, girlfriend, husband, boyfriend, significant other, parents, grandparents: I know she or he is just the cutest thing since like ever and you love them very much. It is really sweet of you to leave a personal message for them as a surprise, but unfortunately, Wikipedia is not a social network. I also, unfortunately, can't leave the article up for just an hour or two until they see it. I recommend tweeting them, leaving them a note on Facebook, IM'ing them, texting them, sending an email, or calling instead of trying to do something for them on Wikipedia. Or surprise them in person and take them out to lunch. I am sure that they will enjoy an in-person visit much more than anything you put on Wikipedia.
If I have not answered your question about why I deleted your article, please feel free to leave me a message. I would be happy to discuss any questions you have.