Someone told me that after panda and penguin these seo plugins can have adverse effect on a wordpress site. How true is it? I am not an expert but it seems every other wordpress user is using plugins such as "All in one seo". I have heard lately about over optimisation penelty and I am wondering should I use a plugin for seo or leave the site as is.
That's BS. BTW I've been using AIOSP for some time but now I don't even bother with installing any SEO plugin when creating new websites because their benefits are negligible in my opinion.
If you look at all the top SEO' websites you will see some use differing "SEO Plugins" some none at all and some, like me mainly, opengraph meta tags but with or without sites are still getting page 1 search results
Using a SEO Plugin for a WordPress website is definitely a good practice. Usually, a WordPress theme will be only optimised for search engines at a minimum level , so you'll have no meta tags and no full control over post titles. Nowadays Google does not require so much this meta tags as in the past , but surely helps to have this defined.
It certainly won't hurt to use an SEO plugin. So long as you've got it set up properly and you're not overusing keywords and all that good stuff. All-in-one-SEO was great several years ago. Nowadays its all about Yoast SEO. Yoast SEO + W3 Total Cache = Speedy website with nice SEO good luck!
Wordpress plugins can never ruin your SEO. After all Google tell you in their guidlines that they like informative sites that not only tell the user what you do, but they tell Google. Without these plugins, sites such as wordpress will not have very good descriptions and titles, therefore it will be a terrible site from a Google perspective
You cannot generalize like that. What if there is an "SEO" plugin that will fill all your pages with keywords? I don't agree with you. Matt Cutts, the head of Google's webspam team, doesn't use any "SEO plugins" on his blog (http://www.mattcutts.com/blog/) and it is doing okay.
There is 2 things i guess why your friend said that : 1- He's a Dump or Newbie and i like what Devtard said : 2- The seo plugin used with proper configuration and USE will never EVER hurt your website rank or getting a Google Penalization... The SEO Plugins work is to economize Time and energy, they handle all what you can do manually (add description, title...etc) I insist on PROPER Configuration and USE because using Seo plugin and Add 25 Keywords for articles isn't a good use