You'll find a small check list of things to not do when you are building a website and expecting to get some traffic. It would either cause a penalty or a loss in SEO juice. 1) No text in Image : A common mistake to avoid ! Content is king in search engine optimization. With CSS3 and html5 you can have some great font design which can be indexed. But if you use it in pictures / images it is a missed opportunity ! Especially in your logo / slogans 2) No Ads : If you can afford to don't place advertisement on your website. It would devaluate your website as it is impacting the users experience. Start the website without ads, you won't earn much at first anyway and place some when you have gained in authority 3) Low Quality / Useless / Irrelevant OBL (outbound links) : Outbound links can be seen as an authority leak of your website. Share your SEO juice with website you want to share with and do it carefully. 4) Cross Linking / Reciprocal Linking : those 2 practices are oldschool and outdated for years. Cross linking doesn't help and reciprocal linking can cause you some penalties. It is quite easy to spot for google. However, in tiered links it is another story. But i'll make a post about it later. 5) No Flash Content : Flash is a crime punished by death penalty since the html 5 went out ! Avoid it at any cost but for videos embedding. The content is badly indexed and there is no trends which would improve the indexing process since html 5 is about to explode. 6) No keywords stuffing : Squeezing as much as you can your keywords in meta tags or content is soo old fashioned and it won't work at all. You can make sure you'll get a penalty doing so 7) No Keywords Dilution : Close from the practice above, it consist in diluting a keyword stuffing in a text instead of comma. Google has pulled semantic statistic for years, has indexed billion of pages. Therefore, even though there is no ideal keyword density, keywords dilution will be spotted and would involved a penalty right away. It was a method used right after the keywords stuffing from the early 00's 8) No cloaking / JS links / Doorway / Invisible text : All those practice are either outdated or you really need to know what you are doing. Cloaking can be done but your method must be accurate and you must be ready to evolve all the time. If you get caught once, your website will be taken down in the abyss of the serps forever. For me it is flagged as to not use at any cost. 9) No iframe content : Doesn't get indexed so unless it brings a serious value to your visitors, avoid it. 10) No Pixel Links : Small and tiny links which are placed under a 1 pixel image are forbidden by google too. Even though the page rank is flowing through images, google is able to pull out the size of your image 11) No meta refresh : Meta Refresh is a way to redirect a page to another after a given amount of time. It decreases the bounce rate and can be assimilated as cheating especially when it is carried accross more than 1 page. It has to be used in some very specific and defined reasons 12) No dynamic URL / Session IDS : Dynamic URL such page.php?login=username;password has to be deindexed manually in order to avoid any kind of duplicated content or even security breach. 13) No Major Structural Problems : The website has to be structured in HTML properly with its own required "grammar". Even though the website is displaying properly, some structural problem may occur and can involve a confusion from the search engines. It isn't thourough but it remains a good list of things i'm checking first when i have to rank a website for a customers. Avoid them at any cost, unless you are an expert and you are absolutely sure about you are doing.