Edit in JSFiddle

$(function(){    


    function containsIgnoreCase(s, q){
        return s.toLowerCase().indexOf(q.toLowerCase()) != -1;
    }

    function Post(title, text){
        this.title = ko.observable(title);
        this.text = ko.observable(text);
        this.selected = ko.observable(false);

        this.containsText = function(query){
            return containsIgnoreCase(this.title(), query) || containsIgnoreCase(this.text(), query);
        }
    }

    viewModel = {
        posts : ko.observableArray([]),
        filterQuery : ko.observable(''),
        editMode : ko.observable(false)
    }

    viewModel.filteredPosts = ko.dependentObservable(function(){
        var query = this.filterQuery();
        if(query){
            var filtered = [];
            $.each(viewModel.posts(), function(i, post){
                if(post.containsText(query)){
                    filtered.push(post);
                }
            });
            return filtered;
        }
        //Not filtering
        return viewModel.posts();
    }, viewModel);

    viewModel.selectedPosts = ko.dependentObservable(function(){
        var result = [];
        $.each(this.posts(), function(i, post){
            if(post.selected()){
                result.push(post);
            }
        });
        return result;
    }, viewModel);

    viewModel.toggleEditMode = function(){
        viewModel.editMode(!viewModel.editMode());
    }

    viewModel.newPost = function(){
        viewModel.posts.push(new Post('',''));
        viewModel.editMode(true);
    }

    viewModel.deletePosts = function(){
        viewModel.posts.removeAll(viewModel.selectedPosts());
    }

    viewModel.posts.push(new Post('title1', 'text1'));
    viewModel.posts.push(new Post('title2', 'text2'));

    ko.applyBindings(viewModel);
});

<div class="container">
    <table>
        <thead>
        <tr>
            <th></th>
            <th>Title</th>
            <th>Text</th>
        </tr>
        </thead>

        <tbody data-bind="template : {name : 'postRow', foreach: filteredPosts}" />
    </table>

    <form>
    <div class="clearfix">
            <a href="#" class="btn primary" data-bind="click : newPost">New post</a>
            <a href="#" class="btn primary" data-bind="visible: editMode, click: toggleEditMode">Save</a>
            <a href="#" class="btn" data-bind="visible: !editMode(), click : toggleEditMode">Edit</a>
            <a href="#" class="btn danger" data-bind="click : deletePosts">Delete</a>
    </div>

    <div class="clearfix">
        <input class="xxlarge" type="text" data-bind="value : filterQuery, valueUpdate:'afterkeydown'" placeholder="Filter"/>
    </div>
    </form>
</div>



<script type="text/html" id="postRow">
    <tr>
        <td><input type="checkbox" data-bind="checked: selected" /></td>
        {{if viewModel.editMode()}}
            <td><input type="text" data-bind="value : title" /></td>
            <td><input type="text" data-bind="value : text" /></td>
        {{else}}
            <td>${title}</td>
            <td>${text}</td>
        {{/if}}
    </tr>
</script>