Per community guidelines:
(1) All posts must contain written text. The best discussion comes out of posts where the author has written something in the post’s body text—an opinion, a question, a request, etc. If you’re attaching a link or photo, at the very least you should describe why the attachment is relevant or valuable to the community. Posts containing only attachments (e.g. just links or photos) and no text will be removed.
(2) Do not attach direct Google Play links to posts. While direct links to Google Play look great on Google+, they can be quite spammy. If you’re looking for design feedback on your app, or are posting about a well-designed app, attach screenshots or a video, and at most paste the link into your post’s body text.
(6) Do not post links only to promote an app, product or service. If your post does not contain some content related to app design, and links to another website for promotional reasons, it will be considered spam.