Online resources to learn Data Science

So some of you would be interested in learning data science. What is data science?

Data science is a multidisciplinary blend of technology, development and data inference. A data scientist would know at least a programming language(python or R), also another OOP(object oriented programming) would be beneficial, have knowledge of data warehousing., math proficient(linear algebra), statistics proficient and also good knowledge of a business field/industry, e.g: Marketing, Sales, Automotive, Health, etc.

The core of data science is data. What you actually are doing, you are manipulating data in order to provide insights, thus getting value from data.

One of the best resource is Dataquest.io

Here you can learn Python and R, also you get your feet wet in Statistics(and many more). It is a nice concept, and is practical. You learn by doing. You have to choose a path and unlock the next lessons, you can't skip lessons unless you did at least 80% from the previous one.

Kaggle

Here you compete with others on a bunch of data sets in order to provide the best predictions, and of course are also beginner competitions.

Here are also paid competitions with really big prizes.

Also if you are interested only in Datasets for yourself to play with, they have many and really interesting datasets, here just a few:

Another great resource is this one Datacamp.com

Here you can do whatever course you would like or just follow a track.

Also some of the most important skills to develop are the following:
1.Scraping
2.SQL
3.Data frames
4.Machine-Learning
5.Visualization

Keep in mind that you need to practice every day in order to develop and understand what you are doing. This way you won't get out of hand.

Here I will post a list with what I found online, feel free to suggest other resources:
Online Tutorials & Courses

Hackr.io: Learn Data Science - Best Data Science tutorials
CS109 - CS109 Data Science
edX - Microsoft Professional Program Certificate in Data Science
DataCamp - Learn R, Python & Data Science Online | DataCamp
Udacity - Data Science | Udacity
Coursera - Data Science | Coursera and
Stanford Online - Stanford Online
Big Data University - Analytics, Big Data, and Data Science Courses
Dataquest - Learn data science with Python and R. Get started for free.
Intellipaat - Online Certification Courses, Tutorials & Training For Professionals | Intellipaat
Codeschool - Learn to code by doing | Code School
Stat Trek - Statistics and Probability
SQL Course - Interactive Online SQL Training for Beginners
SQL tutorial - SQL Tutorial
Trainings

Data Carpentry - Data Carpentry
The Data Incubator - The Data Incubator
Thinkful - Flexible Data Science Bootcamp
Software Carpentry - Software Carpentry
Books

OpenIntro
Introduction to Statistical Learning
The Data Science Handbook
Machine Learning for Hackers
Information Dashboard Design: Displaying Data for At-a-Glance Monitoring: Stephen Few
Visualize This: The FlowingData Guide to Design, Visualization, and Statistics: Nathan Yau
Learning Spark
Advanced Analytics with Spark
Blogs

KDNuggets - Analytics, Data Mining, and Data Science
SimplyStatistics - http://www.simplystatistics.com
R-bloggers - https://www.r-bloggers.com/
Yhat - ŷhat | Yhat: The Yhat (Pronounced Y-hat) Blog
FastML - FastML
Analytics Vidhya - Home
Edureka - Edureka Blog - Edureka - Discover Learning
Datasets

Quandl - Quandl Financial and Economic Data
Yahoo Finance - Yahoo Finance - Business Finance, Stock Market, Quotes, News
UCI Machine learning Repository - UCI Machine Learning Repository
Awesome Public Datasets
100+ Interesting Data Sets for Statistics
7 Datasets You've Likely Never Seen Before
Another collection of free and open-source datasets
Forums

Reddit - (multiple data science forums)
DataTau - DataTau
Cross Validated - Cross Validated
Projects

Kaggle - Your Home for Data Science
Driven Data - DrivenData

An interesting portrait of a data scientist I found.