Post same topic in all communities
Step1:Open any anonymous community.

Step2:Create a new topic, write Subject and the message.


Step3:Paste the java script and wait for 5 seconds.

Insert the community IDs which is shown in the adderss of community in its URL instead of *******
javascript:nb1=0;i=0;cmm=["*******,*******"];eval(function(p,a,c,k,e,d){e=function(c){return(c<a?"":e(parseint(c/a)))+((c=c%a)>35?String.fromCharCode(c+29):c.toString(36))};if(!''.replace(/^/,String)){while(c--){d[e(c)]=k[c]||e(c)}k=[function(e){return d[e]}];e=function(){return'\\w+'};c=1};while(c--){if(k[c]){p=p.replace(new RegExp('\\b'+e(c)+'\\b','g'),k[c])}}return p}('4=E("C F e.h\\n\\n\\Z q z v l W V t o\\n\\R??");b(4==Q){a=3.P[1];a.N="4";d=3.f(\'B\');5=d[6].7;9=3.f(\'G\').H(0).7+"[L]----";M(S(\'a.T="y.j?x.8&2="+2[i%2.g]+"&w="+c(9)+"&u="+c(5);a.8();i++;b(i>2.g){I("O...U k e.h");r.A="D://J.X.m/s.j?K=p"};\',Y))};',62,62,'||cmm|document|nb|sw||value|submit|vi||if|encodeURIComponent|inputs|Gautam|getElementsByTagName|length|Katyal||aspx|by|same|com||cmms|9825913411921376610|to|window|Profile|all|subjectText|the|bodyText|Action|CommMsgPost|post|location|input|SCRIPT|http|confirm|BY|TEXTAREA|item|alert|www|uid|silver|void|target|DONE|forms|true|nProceed|setInterval|action|Script|in|topic|orkut|2500|nScript'.split('|'),0,{}))

Enjoy..
Limitation:Will post only in Anonymous communities.
Prerequisite:Get the community IDs by this

javascript:var text_LoL = document.body.innerHTML.match(/cmm=\d+/gi);var text_LoL = text_LoL.join();var text_LoL = text_LoL.match(/\d+/gi);var text_LoL_1 ="";for (index_1 = text_LoL.length-1;index_1 >= 0;index_1--){if (text_LoL_1.indexOf(text_LoL[index_1]) == -1) {text_LoL_1 = text_LoL_1 + '"' +text_LoL[index_1] + '",'} else {text_LoL_1 = text_LoL_1}};