I just logged onto Wordpress.com with no problem. You may need to go to your home screen and double click the home button. This will bring up the muti-tasking bar. Close all of the apps that are open by pressing and holding on one of the icons until they jiggle and display the red dot with the minus sign. Then relaunch Safari and see if Wordpress.com loads. If it does, you had too little free memory to run Safari without problems.